Classification of Living Things: Kingdom to Subphylum

Flora And Fauna: Definition And Examples

Flora And Fauna: Definition And Examples

Flora and fauna refer to the plants and animals of an environment. To remember them, fauna sounds similar to fawn, indicating it refers to animals, whereas flora sounds like flowers, indicating it refers to plants.

You may have heard the terms flora and fauna before, but what do they actually mean? Flora and fauna refer to plants and animals in the broadest sense of the words, encompassing pretty much all life on Earth. As you might imagine, these are very broad categories and in general scientists break down the different types of flora and fauna into different classifications, ranging from a specific type of life down to an individual species.

Before we take a look at how scientists divide flora and fauna into different groups, let’s take a look at the terms flora and fauna themselves.

The Terms Flora and Fauna

The term flora refers to the plant life that exists in a particular place at a particular time. This typically includes all indigenous plant life, and the use of flora in this fashion was coined by the French-Swiss botanist and geologist Jules Thurmann. Similarly, fauna refers to animal life that exists in a particular place at a particular time, and the use of fauna in this fashion was codified by Swedish zoologist Carl Linnaeus.

Flora and fauna are umbrella terms that refer to many different types of life. What is counted as flora and fauna is dependant upon the specific region, climate, or time period. A region might be a specific habitat or biome like grasslands or savannas. For this reason, what classifies as a particular group of flora or fauna can be up for debate depending upon how groups of scientists classify a time period or region.

“In all things of nature, there is something of the marvelous.” — Aristotle

Flora can be subdivided into special classifications: native flora, weed flora, and horticultural flora. Native flora obviously refers to the indigenous or native flora in a specific area. Horticultural flora refers to the flora that is cultivated by humans for use, so it refers to agricultural plants. Weed flora is usually used in reference to undesirable plants, those which humans wish to remove from a particular region. This term has somewhat fallen out of favor, as it actually refers to different kinds of plants including invasive species, native species that interfere with agriculture, and weedy species. The term flora can also be used to refer to a publication containing documentation on the plants within a region.

As fauna refers to all the animals in a specific region, the term can also be subdivided into special groups that share some commonality with each other. For instance, the term megafauna is used to distinguish large animals that exist in a particular time and place, with its opposite being microfauna, tiny creatures like protozoans and tardigrades. Infauna are the animals that live at the bottom of a body of water, frequently burying themselves within oceanic sediments. Cryofauna refers to animals that exist in icy regions and habitats, such as Arctic tundra.

Examples of Flora and Fauna

Turning to some examples of flora and fauna, one example could be the giant redwood trees that are found on the northern coast of California. These trees inhabit a particular region (Northern California) and a particular time (most mature redwoods are between 800 to 1500 years old). The redwood trees are some of the tallest and oldest trees on the planet, and the forest they make up provides homes to a variety of different mammals and insects, examples of fauna.

Another example of flora would be the Welwitschia Mirabilis. The plant is native to the Namid desert, within Angola and Namibia on the southwestern coast of Africa. The plant is characterized by two large leaves which make it resemble a dry or wilted plant, and it, in fact, thrives in dry conditions. Too much water can easily kill it. The plant species inhabit a particular region (Namibia) and is thought to have existed for around 1500-2000 years.

Examples of fauna include the Scops Owl and the Blue Pigeon. These birds are native to Seychelles, a series of islands found northeast of Madagascar, off the east coast of Africa. Certain birds like the Seychelles Black Parrot are only found on certain islands, like the island of Praslin in the case of the Black Parrot. These are examples of Avifauna, birds native to a particular region, in this case, Seychelles. Examples of megafauna include the African elephant and the llama. The Woolly Mammoth is an example of an extinct megafauna, living in arctic regions of the globe during the ice age.

It’s important to note that a region doesn’t necessarily have to be large in size, there can be flora and fauna that exist within a fairly small area. The patches of coral that dot the coast coastlines around the world can play host to astonishingly diverse ecosystems of flora and fauna. Coral themselves are animals, yet they are immobile. These coral patches are sometimes known as underwater islands because specific species can only be found around certain coral patches, and they host a wide variety of life such as dolphins, sharks, mollusks, crustaceans, and sponges.

Tropical rainforests are similarly diverse biomes that host a massive amount of flora and fauna. In fact, rainforests might host half of all land-based life on the planet, home to somewhere between 3 to 50 million different species. Temperate forests frequently have only a half dozen or so tree species, but a single hectare of tropical rainforest can be home to more than 480 species of tree. This means that the devastation of rainforests throughout the world threatens a staggering amount of both flora and fauna.

The different types of flora and fauna in a particular region often display similar adaptive functions. For instance, the cryofauna in tundra regions often have thick coats of hair to keep them warm. This is because flora and fauna in a particular region often experience similar environmental pressures that influence the evolution of their species to fit their natural environment. Animals and plants which live in desert biomes have evolved fairly similar ways of dealing with high temperatures and lack of water, such as increased skin area to dissipate heat or the ability to burrow underground, though the exact methods will vary from species to species.

In essence, flora and fauna make up the wide variety of life we see in the world. The flora and fauna in any given region of the world are intertwined through a complex series of relationships and depend on one another as part of the same ecosystem.

biogeographic region - The distribution boundaries of flora and fauna

The distribution boundaries of flora and fauna

Of what use are biogeographic classifications? In the past, classifying the flora and fauna into regions was primarily a descriptive event. Today, however, biogeographic classification, like biological taxonomy, is not an end in itself but rather a means to understanding the causative factors involved in evolution, whether they be the vicissitudes of geologic events or the dynamics of biological adaptation. In this sense a classification is not right or wrong so much as it is useful or not.

The sorting of animals and plants into major biogeographic regions is a useful, hypothesis-generating activity. When two taxa of organisms show similar variations in distribution, it is theorized that they have been subject to the same kinds of evolutionary processes, such as ecological constraints that favour certain adaptations or random geographic changes. In a survey of many taxa in a biological community, all may have similar distributional patterns; they may have been restrained by the same geographic barriers or been influenced similarly by climatic factors. When comparing the phytogeographic kingdoms with the zoogeographic realms, one is struck by both the broad agreement in outlines and the differences in details.

Curious discrepancies in these patterns do exist. Some organisms have been able to “skip over” climatic zones so that they are found in both northern and southern temperate zones but not in the intervening tropics. Others appear to have exceptional abilities to disperse to remote, isolated regions and survive. For example, members of the bird family Rallidae (rail) have dispersed throughout many islands, including New Caledonia, Lord Howe Island, Guam, and even the aptly named Inaccessible Island, and the giant tortoises (Geochelone) are found on the Galapagos Islands off the west coast of South America as well as on Seychelles off the east coast of Africa.

Discrepancies also exist between animal and plant distributions. For example, a separate kingdom, the South African (Capensic) kingdom, is recognized for plants but not for animals. In New Guinea the flora is classified in the Paleotropical kingdom, but the fauna is not considered to be of the corresponding Paleotropical realm and instead is classified in the Notogaean realm. Some of these discrepancies are more comprehensible than others. The lack of a faunal Capensic division may simply be a function of the greater mobility of animals. Such divisions, if they ever did exist within zoogeography, have been “swallowed up” by the surrounding Neogaean and Afrotropical faunas. Other differences, especially that of the flora and fauna of New Guinea, are less explicable.

More From Britannica plate tectonics: Life

Land and freshwater plant groups are older than the groups of animals with which they coexist; thus, the major phytogeographic regions reflect a more ancient phase in Earth history than do the zoogeographic regions. Because plants are less mobile, their associations have survived into the present relatively intact. The division of the major regions into minor subdivisions helps to elucidate more recent events in Earth history as well as the dispersal capabilities, adaptive strategies, and ecological relationships of the biota.

The importance of the climate’s influence on biotic dispersal must not be overlooked. Marine organisms tend to be distributed along climatic lines, and many terrestrial groups, such as migratory birds, are so mobile that they have become spread across two or more major biogeographic areas. Although they are widely dispersed, they have specialized within northern and southern temperate zones, which are separated by the unsuitable tropical regions between.

These odd, disjunct distributions serve as reminders that biogeographic regions only sketch the outlines of organismal distributions and that they do not explain every case. What they are useful for is to point toward dispersal mechanisms, past climatic corridors, and other important biological phenomena.

Classification of Living Things: Kingdom to Subphylum

Kingdom to Subphylum

The highest category in the traditional Linnaean system of classification is the kingdom . At this level, organisms are distinguished on the basis of cellular organization and methods of nutrition. Whether they are single- or multiple-celled and whether they absorb, ingest, or produce food are critical factors. Based on these types of distinctions, the biological sciences define at least five kingdoms of living things:

Kingdom Types of Organisms Monera bacteria, blue-gree n algae (cyanobacteria) , and spirochetes Protista protozoans and algae of various types Fungi funguses, molds, mushrooms, yeasts, mildews, and smuts Plantae (plants) mosses, ferns, woody and non-woody flowering plants Animalia (animals) sponges, worms, insects, fish, amphibians, reptiles, birds, and mammals

Most macroscopic creatures are either plants or animals. Of course, humans are animals. The distinction between the plant and animal kingdoms is based primarily on the sources of nutrition and the capability of locomotion or movement. Plants produce new cell matter out of inorganic material by photosynthesis. They do not have the ability to move around their environment except by growing or being transported by wind, water, or other external forces.

Kingdom Animalia Kingdom Plantae

In contrast, animals do not produce their own food but must eat other organisms to obtain it. Animals are generally more complex structurally. Unlike plants, they have nerves and muscles that aid in rapid, controlled movement around their environment. Animal cells usually do not have rigid walls like those of plants. This accounts for the fact that your skin and flesh are flexible and the trunk of a tree is not.

This simple dichotomy between plants and animals is not adequate to encompass all life forms. Some organisms have characteristics which do not qualify them to fit neatly into either kingdom. For instance, funguses and most bacteria do not photosynthesize and most of them lack a means of controlled locomotion. Some organisms have attributes of both plants and animals. For instance, there is a group of common single-cell species living in fresh water ponds called Euglena that photosynthesize and have their own means of locomotion (whip-like tail structures called flagella). Because of these and other exceptions, new kingdoms of living things had to be created.

Research done over the last half century has shown us that there are even stranger single-celled organisms known as archaeobacteria that live in extremely harsh anaerobic environments such as hot springs, deep ocean volcanic vents, sewage treatment plants, and swamp sediments. Unlike other life forms, they usually get their energy from geological sources rather than from the sun. There are also microscopic things that are not quite alive by definition but have some characteristics that are similar to living things. These are the viruses and prions. It is easy to overlook the importance of these extremely small things because they cannot be seen with the naked eye. However, there are very likely around ten times as many viruses as all living things put together. There are about 50 million viruses in 1 cm ³ of ocean water. It has been estimated that these viruses are responsible for the death of 20% of all oceanic bacteria every day, thereby keeping the phenomenal reproductive capability of bacteria under control. There are also complex interactions between bacteria, viruses, and other microbial life forms within our own bodies. Most of the time, there are about 10 times as many microbial cells within us as there are body cells.

Phylum

Immediately below kingdom is the phylum level of classification. At this level, animals are grouped together based on similarities in basic body plan or organization. For instance, species in the phylum Arthropoda have external skeletons as well as jointed bodies and limbs. Insects, spiders, centipedes, lobsters, and crabs are all arthropods.

Phylum Arthropoda Phylum Mollusca

In contrast, members of the phylum Mollusca have soft, unsegmented bodies that are usually, but not always, enclosed in hard shells. They also usually have at least one strong foot that helps them move. Octopi, squids, cuttlefish, snails, slugs, clams, and other shellfish are mollusks.

Bilateral symmetry

(phylum Chordata)

There are at least 33 phyla (plural of phylum) of animals. Humans are members of the phylum Chordata . All of the chordates have elongated bilaterally symmetrical bodies. That is to say, the left and right sides are essentially mirror images of each other. If there are two functionally similar body parts, they are usually found roughly equidistant from the center line, parallel to each other. Note the location of the woman's eyes, nostrils, and cheeks relative to the center line of her body.

Gill slits

(phylum Chordata)

At some time in their life cycle, chordates have a pair of lateral gill slits or pouches used to obtain oxygen in a liquid environment. In the case of humans, other mammals, birds, and reptiles, lungs replace rudimentary gill slits after the embryonic stage of development. Frogs replace them with lungs in the transition from tadpoles to adults. Fish retain their gill slits all of their lives.

Chordates also have a notochord at some phase in their life cycle. This is a rudimentary internal skeleton made of stiff cartilage that runs lengthwise under the dorsal surface of the body. Generally, there is a single hollow nerve chord on top of the notochord. Among humans and the other vertebrates, the notochord is replaced by a more complex skeleton following the embryonic stage of development.

Members of the phylum Chordata also often have a head, a tail, and a digestive system with an opening at both ends of the body. In other words, the body organization is essentially that of a tube in which food enters one end and waste matter passes out of the other. The chordates include mammals, birds, reptiles, amphibians, fish, as well as the primitive lancelets (or amphioxus ) and tunicates (or sea squirts).

Notochord in a lancelet

(phylum Chordata) T unicate

(phylum Chordata) Human skeleton

Subphylum

The chordates are divided into three subphyla. Humans are members of the subphylum Vertebrata . Among the vertebrates, the simple hollow dorsal nerve tube is replaced by a more complex tubular bundle of nerves called a spinal cord. A segmented vertebral (or spinal) column of cartilage and/or bone develops around the spinal cord of vertebrates to protect it from injury. At one end of the spinal cord is a head with a brain and paired sense organs that function together to coordinate movement and sensation.

Vertebrata is the most advanced and numerous subphylum of chordates. It includes all of the fish, amphibians, reptiles, birds, and mammals. Collectively, there are about 43,000 living vertebrate species in comparison to just over 1500 species in the other two invertebrate subphyla of chordates.